WHY RADIATOR FAN STAYS ON AFTER IGNITION IS TURNED OFF

Asked by Mar 22, 2013 at 05:28 AM about the 2000 Jeep Grand Cherokee

Question type: Maintenance & Repair

i RETURNED FROM A 1000 MILE TRIP AND HAD LAST STOPPED ABOUT 100 MILES AWAY FOR GAS AND
ALL WAS FINE.AFTER GETTING HOME(LUCKILY!)WHEN I TURNED THE IGNITION OFF TO WHICH I DID'NT
NOTICE FOR AN HOUR, THE RADIATOR FAN WAS STILL RUNNING. IT HAS RUN THE BATTERY DOWN AND
I'M CHARGING IT NOW.. I HAVE A 2000 4.0 GRAND  CHEROKEE LAREDO. IS IT A RELAY OR SWITCH OR
SOMETHING HOPEFULLY SIMPLE.THE TEMP WAS FINE, THE COOLANT IS GOOD.THE FAN JUST WON'T GO
OFF. I WROTE LAST NIGHT THINKING OF AUX FAN BUT WHEN I LOOKED IN THE LIGHT IT WAS BIG FAN.
THANKS FOR ANY ADVICE AND I TRULY APPRECIATE YOUR SUGGESTIONS.GOD BLESS.

9 Answers

A radiator temperature-sensing switch activates the fan relay at 198 degrees F turns the fan on and controls its operation. Make sure the key is off. Switching relays is the fastest way to check for a bad relay when possible. A Jeep has more than one relay that are the same (go by the relay number on the top or side of the relay) in the fuse box on the driver's side fenderwell. Remove a known good relay and swap it with the radiator fan relay. Operate the vehicle and check the operation of the unit replaced. If the unit works with the fan relay it proves that the relay is not the problem. Test the relay using jumper wires and a voltmeter. Connect one jumper wire from the battery positive terminal to the relay positive terminal. Connect the second jumper wire from the negative terminal of the battery to the negative terminal of the relay. When the negative wire is attached to the relay, the relay should have an audible click as it activates. If the relay fails to click, move the jumper wires to the second set of terminals in the event the wrong terminals were being used. If the relay fails to click it is bad. Check the radiator fan switch if the relay proves to be good. If the fan switch is good, check the radiator fan by using the jumper wires from the battery to the electrical connection on the radiator fan to wire it directly to the battery. If it fails to operate the fan is bad.

18 people found this helpful.
Best Answer Mark helpful

the relay

14 people found this helpful.
9,235

Here ya go. its under ft. bumper on rt side. If ya remove pass. side headlamp, you can cut an accecc hole and get to it. otherwise you need to remove ft. bumper cover.

19 people found this helpful.
380

I have the same problem with my fan on my 2000 Jeep Grand Cherokee Laredo 2 wheel drive v6 4 liter my fan won't shut off bought new relay switches it works for a little bit then the fan stays off when I have the car shut off it just keeps on running till it kills my battery the fan will not shut off

22 people found this helpful.
380

I bought a relay switch are ready it works for a little bit but then when I get home and shut off the car the fan keeps on running until it kills my battery

14 people found this helpful.
30

I want to know myself

3 people found this helpful.
80

I have a 2002 Jeep Grand Cherokee and when I returned from work the truck fan wouldn't stop running. After an hour, I disconnected one of the battery cable and the fan stop. Since I am a 58 year old woman and don't have any knowledge on cars repair. I reconnect the battery cable and take the truck to the dealer and pray that I don't have to pay too much money to have the truck repair.

8 people found this helpful.

I have a 2003 jeep cherokee and it keeps overheating my mechanic has changed the fan, relay twice and still overheats on slow traffic or hot day it dors have high milrs 185K

20

I am having a similar issue with my 99 grand cherokee 4.0, fan will not shut off i have to pull the fuse, i have replaced the relay and that was not the issue, the temperature Gage on the dash is working so i am thinking its not the temp sending unit, could it be a computer problem or something else? any help would be appreciated.

2 people found this helpful.

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